'\"macro stdmacro
.\"
.\" Copyright (c) 2000 Silicon Graphics, Inc.  All Rights Reserved.
.\"
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.\" under the terms of the GNU General Public License as published by the
.\" Free Software Foundation; either version 2 of the License, or (at your
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.\" or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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.\"
.TH PMLOOKUPNAME 3 "PCP" "Performance Co-Pilot"
.SH NAME
\f3pmLookupName\f1 \- translate performance metric names into PMIDs
.SH "C SYNOPSIS"
.ft 3
.ad l
.hy 0
#include <pcp/pmapi.h>
.sp
int pmLookupName(int \fInumpmid\fP,
'in +\w'int pmLookupName('u
const\ char\ **\fInamelist\fP,
pmID\ *\fIpmidlist\fP);
.in
.sp
cc ... \-lpcp
.hy
.ad
.ft 1
.SH DESCRIPTION
Given a list in
.I namelist
containing
.I numpmid
full pathnames for performance metrics from a Performance Metrics Name
Space (PMNS),
.B pmLookupName
returns the list of associated
Performance Metric Identifiers (PMIDs) via
.IR pmidlist .
.PP
The result from
.B pmLookupName
depends on the presence of any lookup failures, their severity and the
number of metrics being looked up.
.IP 1. 4n
If there are no lookup failures, the return value will be
.IR numpmid .
.IP 2. 4n
If a fatal error is encountered, the return value will be less than 0.
For example
.BR PM_ERR_TOOSMALL ,
.B PM_ERR_NOPMNS
or
.BR PM_ERR_IPC .
.IP 3. 4n
If
.I numpmid
is greater than one and non-fatal error(s) are encountered, the
return value is the number of metric names that have successfully been
looked up (greater than or equal to zero and less than or equal to
.IR numpmid ).
.IP 4. 4n
If
.I numpmid
is one and a non-fatal error is encountered, the return value is the
error code (less than zero).
.PP
When errors are encountered, any metrics that cannot be looked up
result in the corresponding element of
.I pmidlist
being set to
.BR PM_ID_NULL .
.PP
The slightly convoluted error protocol allows bulk lookups, then
probing for more error details in the case of a specific failure,
as shown in the
.B EXAMPLES
section below.
.PP
Note that the error protocol guarantees there is a 1:1 relationship
between the elements of
.I namelist
and
.IR pmidlist ,
hence both lists contain exactly
.I numpmid
elements.
For this reason, the caller is expected to have preallocated a suitably
sized array for
.IR pmidlist .
.SH EXAMPLE
.nf
.ft CR
#include <pcp/pmapi.h>

#define NUMPMID (sizeof(names)/sizeof(const char *))
const char *names[] = {
		     "sample.bin",
		     "sample",
		     "sample.bog",
		     "sample.secret.bar",
		     "sample.secret.bar.bad"
		   };
pmID pmids[NUMPMID];

int
main(int argc, char **argv)
{
    int	sts;
    int	numpmid = NUMPMID;

    pmNewContext(PM_CONTEXT_HOST, "local:");

    sts = pmLookupName(numpmid, names, pmids);

    if (sts < 0) {
	fprintf(stderr, "pmLookupName failed: %s\n", pmErrStr(sts));
	exit(1);
    }
    if (sts != numpmid) {
	/*
	 * some of the lookups failed ... report the reason(s)
	 */
	int	i;

	for (i = 0; i < numpmid; i++) {
	    if (pmids[i] != PM_ID_NULL) continue;
	    /* this one failed */
	    sts = pmLookupName(1, &names[i], &pmids[i]);
	    fprintf(stderr, "%s: lookup failed: %s\n", names[i], pmErrStr(sts));
	}
	exit(1);
    }

    /* all good ... */
    ...
}

.ft
.fi
.SH DIAGNOSTICS
.IP \f3PM_ERR_TOOSMALL\f1
.I numpmid
must be at least 1
.IP \f3PM_ERR_NOPMNS\f1
Failed to access a PMNS for operation.
Note that if the application hasn't a priori called
.BR pmLoadNameSpace (3)
and wants to use the distributed PMNS, then a call to
.B pmLookupName
must be made after the creation of a context (see
.BR pmNewContext (3)).
.IP \f3PM_ERR_NAME\f1
.I namelist[0]
does not correspond to a valid metric name in the PMNS.
.IP \f3PM_ERR_NONLEAF\f1
.I namelist[0]
refers to a node in the PMNS but it was
not a leaf node.
.IP \f3PM_ERR_*\f1
Other diagnostics are for protocol failures when
accessing the distributed PMNS.
.SH SEE ALSO
.BR PMAPI (3),
.BR pmGetChildren (3),
.BR pmGetChildrenStatus (3),
.BR pmGetConfig (3),
.BR pmLoadNameSpace (3),
.BR pmNameID (3),
.BR pmNewContext (3),
.BR pcp.conf (5)
and
.BR pcp.env (5).

.\" control lines for scripts/man-spell
.\" +ok+ {from PM_ERR_*}
.\" +ok+ NUMPMID argc argv sts {from example C code}
